1. Field of the Invention
The present invention relates to an inkjet print head for ejecting ink, a manufacturing method for the inkjet print head, and an inkjet print head mounting tool employed for the manufacturing method.
2. Description of the Related Art
A method that employs an electro-thermal converting element is one of the typical ink ejection methods used for inkjet print heads employed for inkjet printing apparatuses.
For this type of inkjet printing apparatus, a technique disclosed in Japanese Patent Laid-Open No. 2006-056243 provides for an electrical connection to be established between an electric wiring member and a terminal to be connected to an electro-thermal converting element.
In the inkjet printing head disclosed in Japanese Patent Laid-Open No. 2006-056243, a flexible wiring member, which serves as a support member, is arranged under a printing element board on which nozzles are formed. For this arrangement, first and second wiring layers are formed, using copper foil patterning, on respective sides of the flexible wiring member, which is made of a polyimide resin base film. Then, bumps are formed on electrode terminals formed by the first wiring layer of the flexible wiring member, and the printing element board and the flexible wiring member are electrically connected by bonding the bumps to electrodes on the reverse face of the printing element board. Thus, electric power, and the electric signals that are required to control the ejection of ink, can be transmitted from the flexible wiring member to the printing element board.
A manufacturing process that prevents an IC chip from being scratched while being mounted is disclosed in Japanese Patent Laid-Open No. 2001-134916.
FIG. 10 is a diagram illustrating this IC chip manufacturing process. An IC chip 12 is a bare chip, across the entire surface of which, opposite a connection electrode bearing surface, a protective metal or resin layer 19 has been laminated. Arranged on the bottom of the IC chip 12 are bumps 45, which were previously formed on connection electrodes (not shown) using Au balls. On a flexure member 13 made of a stainless steel plate, a thin film pattern has been formed, using the same well known patterning method as used for fabricating a printed circuit, such as a flexible printed circuit (FPC), on a thin metal board.
The bumps 45 on the IC chip 12 and the flexure 13 are bonded together in the following manner. First, an ultrasonic attraction head 46, called a nozzle, is pressed against the surface of the IC chip 12, and the IC chip 12 is held (picked up) and is positioned at a connection pad portion (not shown) of an Au layer 44. Then, the IC chip 12 is pressed down, in the direction indicated by an arrow 47, until the Au ball bumps 45 on the IC chip 12 contact connection pads 44 on the thin film pattern. Subsequently, an ultrasonic wave, which vibrates as indicated by an arrow 48 (laterally), is applied to the IC chip 12 via the nozzle 46. When a predetermined pressure (a load) and the ultrasonic vibration are applied in this manner, the Au ball bumps 45 of the IC chip 12 and the connection pads (not shown) on the Au layer 44 are bonded together by fusion within a short period of time.
Furthermore, in Japanese Patent Laid-Open No. 2005-032944, a technique is disclosed whereby ultrasonic vibration is used to cause an electronic part held by a print head to reciprocate horizontally, so that the electronic part is bonded to a board under pressure.
Recently, demands have increased for inkjet printing apparatuses that have reduced prices, are more compact, and provide multicolor printing. In response to these demands, improvements are also being sought in the arrangements and the manufacturing methods used for inkjet print heads.
A technique for the pressure-bonding of electronic parts to a board using ultrasonic vibration is also disclosed in Japanese Patents Laid-Open Nos. 2004-336071 and 2005-032944, described above. The bonding technique that employs ultrasonic vibration can reduce bonding periods, compared with the bonding technique that employs an adhesive or solder, and is an effective means for reducing the manufacturing costs for inkjet print heads. Thus, the bonding technique using ultrasonic vibration, disclosed in Japanese Patent Laid-Open No. 2005-032944, can be usefully applied for the bonding of flow path formation members to flexible wiring members, which serve as support members, for an inkjet print head described in Japanese Patent Laid-Open No. 2006-056243.
However, according to the bonding technique that employs ultrasonic vibration, described in Japanese Patent Laid-Open Nos. 2004-336071 and 2005-032944, an electronic part might be scratched when the electronic part is reciprocated horizontally by ultrasonic vibration. Therefore, in a case wherein the ultrasonic bonding technique is applied to bond the nozzle formation member to the wiring member of an inkjet print head described in Japanese Patent Laid-Open No. 2006-056243, the orifice surface of the nozzle formation member would be scratched, and wettability of the orifice surface relative to ink would be changed, so that the ejection direction might be deviated.
In Japanese Patent Laid-Open No. 2001-134916, a proposal is provided for the formation of a protective layer on the reverse face of a chip to prevent the chip being scratched due to contact with an ultrasonic nozzle. Therefore, the protective layer forming technique described in Japanese Patent Laid-Open No. 2001-134916 may be applied for an inkjet print head described in Japanese Patent Laid-Open No. 2006-056243, and then, ultrasonic bonding may be performed. That is, a protective layer may be formed on one face of an ink flow path formation member described in Japanese Patent Laid-Open No. 2006-056243, and the ink flow path formation member may then be bonded to an electrical wiring board by pressing an ultrasonic nozzle against the protective layer on the ink flow path formation member. Using this method, damage to the ink flowpath formation member can be reduced.
However, the inkjet print head wherein an ink flow path member is formed on the printing element board is so designed that an adhesive layer is located between the printing element board and the ink flow path formation member, and therefore, with the adhesive layer, the adhesiveness of the two members is increased and this can hinder or prevent the ink flow path formation member from being peeled off easily. Therefore, when ultrasonic vibration is applied to the printing element board by the ultrasonic nozzle, via the ink flow path member, some minute peeling, such that an interference pattern can be observed, could occur between the printing element board and the ink flow path formation member.